/*
 * Copyright (C) 2013 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.client.android;

import java.util.ArrayList;
import java.util.Collection;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.PreferenceFragment;
import android.preference.PreferenceScreen;

public final class PreferencesFragment extends PreferenceFragment implements
		SharedPreferences.OnSharedPreferenceChangeListener {

	private CheckBoxPreference decode1D;
	private CheckBoxPreference decodeQR;
	private CheckBoxPreference decodeDataMatrix;

	@Override
	public void onCreate(Bundle icicle) {
		super.onCreate(icicle);
		addPreferencesFromResource(R.xml.preferences);

		PreferenceScreen preferences = getPreferenceScreen();
		preferences.getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
		decode1D = (CheckBoxPreference) preferences.findPreference(PreferencesActivity.KEY_DECODE_1D);
		decodeQR = (CheckBoxPreference) preferences.findPreference(PreferencesActivity.KEY_DECODE_QR);
		decodeDataMatrix = (CheckBoxPreference) preferences.findPreference(PreferencesActivity.KEY_DECODE_DATA_MATRIX);
		disableLastCheckedPref();
	}

	@Override
	public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
		disableLastCheckedPref();
	}

	private void disableLastCheckedPref() {
		Collection<CheckBoxPreference> checked = new ArrayList<CheckBoxPreference>(3);
		if (decode1D.isChecked()) {
			checked.add(decode1D);
		}
		if (decodeQR.isChecked()) {
			checked.add(decodeQR);
		}
		if (decodeDataMatrix.isChecked()) {
			checked.add(decodeDataMatrix);
		}
		boolean disable = checked.size() < 2;
		CheckBoxPreference[] checkBoxPreferences = { decode1D, decodeQR, decodeDataMatrix };
		for (CheckBoxPreference pref : checkBoxPreferences) {
			pref.setEnabled(!(disable && checked.contains(pref)));
		}
	}
}
